In May, it said malware was found in fewer than 300 restaurants starting in the fall of 2015. About a month later, it said two types of malware were found and the number of restaurants affected was "considerably higher."

There are more than 5,700 U.S. Wendy's restaurants.

Wendy's said Thursday it would post a list of affected restaurants on its website. As of Thursday morning, the list wasn't posted because of "technical difficulties."

But by the afternoon, the company had posted a tool that lets users enter their state and county to see which restaurants are affected. Click here to learn if a restaurant you visited is on the list.